System.LimitException: Too many DML rows: 10001 when updating one record

Question

So in attempting to write a trigger to roll-up numerical values via a lookup field, I appeared to have made a mistake in the code so it updates enough records to throw an error. I thought the way it's written would only update the Account after insert of a Time_Item__c.

Class:

    public class LookupCalculation{

    public enum Method {COUNT, SUM, MIN, MAX, AVG} 

    private string sobjectParent, 
                   relationName, 
                   formulaParent, 
                   sobjectChild, 
                   parentfield, 
                   fieldChild;

    public LookupCalculation(string mysobjectParent, string myrelationName, string myformulaParent,
                             string mysobjectChild, string myparentfield, string myfieldChild){
        sobjectParent = mysobjectParent;
        relationName = myrelationName;
        formulaParent = myformulaParent;
        sobjectChild = mysobjectChild;
        parentfield = myparentfield;
        fieldChild = myfieldChild;
    }

    public void Calculate(Method calculation, List<sobject> childList){
        set<Id> parentIdSet = new set<Id>();
        for(sobject sobj : childList)
            parentIdSet.add((Id) sobj.get(parentfield));
        string soqlParent = 'select id, (select ' + fieldChild + ' from ' + relationName + ') from ' + sobjectParent + '';
        List<sobject> parentList = Database.query(soqlParent);

        for(sobject parent : parentList){
            List<sobject> children = parent.getSObjects(relationName);
            if(children == null)
                children = new List<sobject>();
            Decimal counter = (mustSum(calculation))? 0 : null;
            //if(calculation == Method.COUNT)
              //  counter = children.size();
            for(sobject child : children){
                Decimal value = (Decimal) child.get(fieldChild);
                if(mustSum(calculation) && value != null)
                    counter += value;
                //else if(calculation == Method.MIN && (counter == null || value < counter))
                  //  counter = value;
                //else if(calculation == Method.MAX && (counter == null || value > counter))
                  //  counter = value;
            }
           // if(calculation == Method.AVG && children.size() > 0)
             //   counter = counter / children.size();
            parent.put(formulaParent, counter);
        }
        update parentList;
    }

    private boolean mustSum(Method calculation){
        return (calculation == Method.SUM || calculation == Method.AVG);
    }

}

Trigger:

    trigger TimeItemRollupAcct on Time_Item__c (after insert,after update,after delete,after undelete) {

    /*******************TO BE CUSTOMIZED*********************/
    string mysobjectParent = 'Account',      // Parent sobject API Name
           myrelationName = 'Time_Items__r', // Api name of the relation between parent and child (ends with __r)
           myformulaParent = 'ApexHours__c',        // Api name of the number field that will contain the calculation
           mysobjectChild = 'Time_Item__c',  // Child sobject API Name
           myparentfield = 'AccountTime__c', // Api name of the lookup field on chield object
           myfieldChild = 'Hours__c';          // Api name of the child field to roll up

    LookupCalculation.Method method = LookupCalculation.Method.SUM; //Selected method: could be COUNT, SUM, MIN, MAX, AVG
    /*******************************************************/

    LookupCalculation calculation = new LookupCalculation(mysobjectParent, myrelationName, myformulaParent,
                                                          mysobjectChild, myparentfield, myfieldChild);
    List<sobject> objList = new List<sobject>((List<sobject>) Trigger.new);

    if(Trigger.isDelete)
        objList = Trigger.old;
    if(Trigger.isUpdate)
        objList.addAll((List<sobject>) Trigger.old);
    calculation.calculate(method, objList);
}

Answer 1

Your query should only be returning accounts that were inserted/updated in the trigger. Your current code is selecting all accounts.

You need to update your query as shown below:

String soqlParent = 'select id, (select ' + fieldChild + ' from ' + relationName
          + ') from ' + sobjectParent + ' where id in :parentIdSet';

Without this where condition your code is selecting all Accounts in the org no matter how many were updated in the trigger.

Answer 2

By looking at your code I am not 100% sure where your issue is by I would say most probably it is because it is falling into a infinite loop of trigger calls, which I guess would be time item trigger > Account trigger > something else > time item trigger. Since your current code has no mechanism preventing that.

I would suggest adding a static variable recording whether you are inside a time item trigger or not, if that equals to true, you don't want to execute your time item trigger code.